Nodes and methods for positioning

ABSTRACT

A method in an LCS server of a wireless communication system is provided for positioning of an LCS target. Information is obtained relating to a first predefined geographical area, where it has been determined that a probability that the LCS target is located within the first predefined geographical area is below a threshold. A request is received for a positioning of the LCS target and the obtained information relating to the first predefined geographical area is used for the positioning of the LCS target.

PRIORITY APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/266,937, filed on Oct. 28, 2011, which is the U.S. national phase ofinternational application no. PCT/SE2011/050509 filed 27 Apr. 2011 whichdesignated the U.S. and claims priority to U.S. Provisional ApplicationNo. 61/431,693 filed 11 Jan. 2011, and the entire contents of each ofwhich are hereby incorporated by reference.

TECHNICAL FIELD

The technical field of the present disclosure relates to positioning inwireless communication systems. More particularly, the technologyrelates to a Location Services (LCS) server, to an LCS client, and to amethod for positioning of an LCS target.

BACKGROUND

The Universal Mobile Telecommunication System (UMTS) is one of the thirdgeneration mobile communication technologies designed to succeed GSM.3GPP Long Term Evolution (LTE) is a project within the 3^(rd) GenerationPartnership Project (3GPP) to improve the UMTS standard to cope withfuture requirements in terms of improved services such as higher datarates, improved efficiency, and lowered costs. The Universal TerrestrialRadio Access Network (UTRAN) is the radio access network of a UMTS andEvolved UTRAN (E-UTRAN) is the radio access network of an LTE system. Inan UTRAN and an E-UTRAN, a user equipment (UE) is wirelessly connectedto a Base Station (BS) commonly referred to as a NodeB and an evolvedNodeB (eNodeB) respectively. Each BS serves one or more areas referredto as cells.

The possibility of identifying the geographical location of users in thewireless networks has enabled a large variety of commercial andnon-commercial services, e.g., navigation assistance, social networking,location-aware advertising, and emergency services. Different servicesmay have different positioning accuracy requirements imposed by theapplication. Furthermore, some regulatory requirements on thepositioning accuracy for basic emergency services exist in somecountries, such as E911 from the Federal Communications Commission (FCC)in US and corresponding E112 in Europe.

In many environments, the position may be accurately estimated by usingpositioning methods based on Global Positioning System (GPS). However,GPS is known to be associated with high costs due to higher UEcomplexity, a relatively long time to first positioning fix, and a highUE energy consumption due to a need for large computational resources,resulting in fast battery drain. Today's networks often have apossibility to assist UEs in order to improve the terminal receiversensitivity and the GPS startup performance through Assisted-GPS (A-GPS)positioning. However, GPS or A-GPS receivers are not necessarilyavailable in all wireless UEs, and some wireless communications systemsdo not support A-GPS. Furthermore, GPS-based positioning may often haveunsatisfactory performance in urban canyons and indoor environments.There is therefore a need for complementary terrestrial positioningmethods. There are a number of different terrestrial positioningmethods. One example is Observed Time Difference of Arrival (OTDOA) inLTE.

Nevertheless, methods with traditionally lower accuracy such as thoseexploiting cell identities or fingerprints are still of high importanceand may become particularly important for dense wireless networkdeployments. In dense network deployments the coverage area of lowerpower BSs is typically small and the resulting positioning results maytherefore be quite accurate. These positioning results are alsoachievable at a very short response time, and with low complexity andresource consumption. Low resource consumption is particularly importantfor talk time and standby device performance.

The three key network elements in an LTE positioning architecture arethe Location Services (LCS) Client, the LCS target and the LCS Server.The LCS Server is a physical or logical entity managing positioning foran LCS target by collecting measurements and other location information,assisting the UE in performing measurements when necessary, andestimating the LCS target location. An LCS Client is a software and/orhardware entity that interacts with an LCS Server for the purpose ofobtaining location information for one or more LCS targets. The LCStarget is the entity that is being positioned. LCS Clients may reside inthe LCS targets themselves. In the positioning procedure, an LCS Clientsends a positioning request to an LCS Server to obtain locationinformation, and the LCS Server processes and serves the receivedrequest and sends the positioning result and optionally a velocityestimate to the LCS Client. The positioning request may originate fromthe UE or the network.

In LTE, there exist two positioning protocols operating via the radionetwork: the LTE Positioning Protocol (LPP) and the LTE PositioningProtocol annex (LPPa). The LPP is a point-to-point protocol between theLCS server and the LCS target, used for the positioning of the LCStarget. LPP may be used both in a user plane and a control planepositioning procedure, and multiple LPP procedures are allowed in seriesand/or in parallel thereby reducing latency. LPPa is a protocol betweenthe eNodeB and the LCS server specified only for control planepositioning procedures, although it still may assist user planepositioning by the querying of eNodeBs for information and measurements.A Secure User Plane Location (SUPL) protocol is used as a transportprotocol for LPP in the user plane.

A block diagram illustrating an example of a high-level positioningarchitecture is given in FIG. 1. The LCS target is a UE 150, and the LCSserver 100 is an Evolved Serving Mobile Location Center (E-SMLC) 101.The LCS server 100 may also comprise a SUPL Location Platform (SLP) 102.The control plane positioning protocols LPP between the UE 150 and theE-SMLC 101, LPPa between an eNodeB 130 and the E-SMLC 101, andLCS-Application Protocol (AP) between a Mobile Management Entity (MME)120 in a Core Network (CN) and the E-SMLC 101, are illustrated witharrows. The user plane positioning protocols are also illustrated andcomprises SUPL/LPP between the UE 150 and the SLP 102, and the SUPLbetween the UE 150 and the SLP 102. The SLP 102 may comprise twocomponents, a SUPL Positioning Center (SPC) and a SUPL Location Center(SLC), which may also reside in different nodes. In an exampleimplementation, the SPC has a proprietary interface with the E-SMLC 101,and Llp interface with the SLC, and the SLC part of the SLP communicateswith a Packet data network GateWay (P-GW) 160 and an external LCS Client110. Additional positioning architecture elements may also be deployedto further enhance performance of specific positioning methods. Forexample, deploying radio beacons 140 is a cost-efficient solution whichmay significantly improve positioning performance indoors and alsooutdoors by allowing more accurate positioning, for example, withproximity location techniques.

Positioning results may be signaled between:

-   -   The LCS target 150 and the LCS server 100, e.g. over the LPP;    -   LCS/positioning servers 100, such as between the E-SMLC and the        SLP, over standardized or proprietary interfaces;    -   The LCS/positioning server 100 and other network nodes, such as        between the E-SMLC and the MME, a Mobile Switching Centre (MSC),        aGateway Mobile Location Center (GMLC), Operation and        Maintenance (O&M) nodes or Self Organizing Nodes (SON);    -   The LCS/positioning server 100 and the LCS client 110, such as        between the E-SMLC and a Public Safety Answer Point (PSAP) or        between the SLP and an external LCS client.

To meet Location Based Services (LBS) demands, the LTE network willdeploy a range of complementing methods characterized by differentperformance in different environments. Depending on where themeasurements are conducted and the final position is calculated, themethods may be UE-based, UE-assisted or network-based, each with its ownadvantages. The following methods are available in the LTE standard forboth the control plane and the user plane:

-   -   Cell Identity (CID) positioning;    -   UE-assisted and network-based Enhanced-CID (E-CID), including        network-based Angle of Arrival (AoA) positioning;    -   UE-based and UE-assisted A-GPS positioning, or the more general        Assisted Global Navigation Satellite System (A-GNSS)        positioning; and    -   UE-assisted OTDOA positioning.

Hybrid positioning methods, fingerprinting positioning, and AdaptiveECID (AECID) do not require additional standardization and are thereforealso possible in LTE. Furthermore, there may also be UE-based versionsof the methods above, e.g. UE-based GNSS/GPS, and UE-based OTDOA. Theremay also be some alternative positioning methods such as civic addressbased positioning or proximity based location. Uplink Time Difference OfArrival (UTDOA) currently under discussion in 3GPP may also becomestandardized in a coming LTE release.

CID Positioning:

Cellular systems are divided into cells, each cell served by onespecific BS. Each BS may serve more than one cell. One important pointfrom a positioning and navigation perspective is that the cell where aspecific UE is located is known in the cellular system. Hence, afterdetermination of the geographical area covered by a specific cell, itmay be stated that the UE is located somewhere within said geographicalarea, as long as it is connected and the reported cell identity of theserving cell is equal to the cell identity of the particulargeographical area. In several systems, the preferred representation ofthe geographical area of the cell is given by the cell polygon format.The cell area described by a polygon is an approximation, and thepolygon is normally pre-determined in the cell-planning tool torepresent the cell area with a certain confidence. The confidence is theprobability that the terminal is actually located within the reportedarea, in this case bounded by the cell polygon. Although the accuracy ofthe method is limited by the cell range, its main advantages are a verylow response time as well as the fact that it has no impact on the UE,it is easy to implement, and it is widely spread and always availablewhere there is cellular coverage. To exploit these advantages andenhance the CID technique, the accuracy of CID is further improved inthe E-CID method.

E-CID Positioning:

E-CID methods exploit four sources of position information: the CID anda corresponding geographical description of the serving cell, a TimingAdvance (TA) of the serving cell, the CIDs and corresponding signalmeasurements of measured cells, which may be up to 32 cells in LTE,including the serving cell, as well as AoA measurements. The followingtechniques are commonly used for E-CID:

-   -   CID and TA: A combination of the geographical cell description,        the eNodeB position, and the distance between the eNodeB and the        UE obtained from a TA measurement;    -   Signal strength: Distance measures are derived from signal        strengths measured in the UE and combined with cell polygons as        for CID and TA;    -   AoA: As an example the angle of a UE with respect to a reference        direction which is the geographical North may be defined.    -   AoA combined with TA, exploiting the orthogonal directionality        of the two involved measurements.

TDOA or Time of Arrival (TOA) Based Methods Such as OTDOA, UTDOA orGNSS/A-GNSS:

OTDOA is a method based on time difference measurements conducted ondownlink positioning reference signals received from multiple locations,where the user location is further calculated by multi-lateration.UTDOA, which is an uplink version of OTDOA, is a method that exploitsuplink time of arrival or time difference of arrival measurementsperformed at multiple receiving points. The UTDOA measurements are to bebased on Sounding Reference Signals (SRS). A-GNSS/GNSS is a group ofmethods using satellite signal measurements, where GPS developed in theUS and Galileo developed in Europe are some examples of GNSS systemswith close to global coverage.

Radio Frequency (RF) Fingerprinting:

The method exploits received signal strength measurements from the UEtogether with the corresponding cell identities to map onto apredetermined geographical map of the radio properties. The maps may beobtained by extensive site surveying or by radio signal strengthsimulation software.

AECID:

The AECID method enhances fingerprinting positioning performance byextending the number of radio properties that are used. At least CIDs,TA and AoA may be used in addition to received signal strengths.Corresponding databases are automatically built up by collecting highprecision OTDOA and A-GNSS positions, tagged with measured radioproperties. The AECID procedure comprises the following steps forbuilding up information supporting the positioning:

-   -   1. Tagging of high-precision position results (e.g. A-GPS        measurements) with at least one of CIDs of detected cells,        auxiliary connection information (e.g. radio access bearer and        time), and quantized auxiliary measurements (e.g. TA or signal        strength).    -   2. Collection of all high precision measurements with the same        tag in high precision measurement clusters.    -   3. Calculation of a tagged polygon which contains a        pre-specified fraction of said clustered high precision position        measurements in the interior, thereby providing a polygon with a        known confidence value. The confidence is the probability that        the UE is actually located in the reported area.    -   4. Storage of said tagged polygons in a database of polygons.

When an AECID positioning is to be performed, the following steps areperformed:

-   -   a) Determination of at least one of CIDs of detected cells,        auxiliary connection information, and quantized auxiliary        measurements;    -   b) Formation of the tag;    -   c) Retrieval of the polygon corresponding to said tag, from the        information built up as described above.    -   d) Reporting of said polygon.

According to the 3GPP definition, a heterogeneous network comprises twoor more layers, where each layer is served by one type of BS class ortype. A heterogeneous network may enhance capacity in dense trafficareas or hotspots and may also be used for coverage extension. Oneexample is a two-layered macro/femto heterogeneous network, where themacro cell layers and femto cell layers typically comprise macro BS andhome BS, respectively. A home BS, sometimes also called a femto BS,typically serves private premises or small office environment. Anothermain characteristic of the home BS is that it is typically owned by aprivate subscriber. An access control mechanism for the home BS decidesif a given UE may or may not connect to that home BS. In UTRAN andE-UTRAN, a concept of Closed Subscriber Groups (CSG) exists. Accordingto the CSG concept only a subset of UEs, defined by the owner of thehome BS, may wirelessly access or connect to that particular home BS.Hence wireless access for other UEs is denied by the CSG based home BS.Therefore different cell reselection rules will apply for different UEswith CSG cells in the macro deployment area. This is not taken intoaccount in conventional positioning methods that are based on cellidentities, which may make the positioning results inaccurate.

SUMMARY

An object is therefore to address some of the problems and disadvantagesoutlined, and to allow the usage of information relating to geographicalareas where it is unlikely that the UE is located, for the purpose ofpositioning.

In accordance with an embodiment, a method in a location services, LCS,server of a wireless communication system, for positioning of an LCStarget, is provided. The method comprises obtaining information relatingto a first predefined geographical area. It has been determined that aprobability that the LCS target is located within the first predefinedgeographical area is below a threshold. The method further comprisesreceiving a request for a positioning of the LCS target, and using theobtained information relating to the first predefined geographical areafor the positioning of the LCS target.

In accordance with a second embodiment, a method in a location services,LCS, client of a wireless communication system, for positioning of anLCS target, is provided. The positioning is managed by an LCS serverinteracting with the LCS client for the positioning of the LCS target.The method comprises receiving information relating to a firstpredefined geographical area from the LCS server, wherein it has beendetermined that a probability that the LCS target is located within thefirst predefined geographical area is below a threshold. The methodfurther comprises using the received information for the positioning ofthe LCS target.

In accordance with a third embodiment, a location services, LCS, serverconfigured to be used in a wireless communication system for positioningof an LCS target is provided. The LCS server comprises a processing unitconfigured to obtain information relating to a first predefinedgeographical area, wherein it has been determined that a probabilitythat the LCS target is located within the first predefined geographicalarea is below a threshold. The processing unit is further configured toreceive a request for a positioning of the LCS target, and use theobtained information relating to the first predefined geographical areafor the positioning of the LCS target.

In accordance with a fourth embodiment, a location services, LCS, clientconfigured to be used in a wireless communication system for positioningof an LCS target is provided. The positioning is managed by an LCSserver interacting with the LCS client for the positioning of the LCStarget. The LCS client comprises a processing unit configured to receiveinformation relating to a first predefined geographical area from theLCS server, wherein it has been determined that a probability that theLCS target is located within the first predefined geographical area isbelow a threshold. The processing unit is further configured to use thereceived information for the positioning of the LCS target.

An advantage of particular embodiments is that using informationrelating to geographical areas where it is unlikely that the UE islocated in positioning procedures makes the positioning of the UE moreaccurate.

Other objects, advantages and features of embodiments will be explainedin the following detailed description when considered in conjunctionwith the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating schematically the positioningarchitecture in an LTE system.

FIG. 2 is a schematic illustration of an example of two overlappingcells.

FIGS. 3 a-b are schematic illustrations illustrating an example of acell with an activity that varies over time.

FIG. 4 a is a schematic illustration of two overlapping areas describedas polygons.

FIGS. 4 b-d are schematic illustrations of some examples of how todescribe the areas.

FIGS. 4 e-f are schematic illustrations of some examples of areasubtraction algorithms.

FIGS. 5 a-c are flowcharts of the method in the LCS server according toembodiments.

FIGS. 6 a-b are flowcharts of the method in the LCS client according toembodiments.

FIGS. 7 a-b are block diagrams schematically illustrating an LCS serverand an LCS client according to embodiments.

DETAILED DESCRIPTION

In the following, different aspects will be described in more detailwith references to certain embodiments and to accompanying drawings. Forpurposes of explanation and not limitation, specific details are setforth, such as particular scenarios and techniques, in order to providea thorough understanding of the different embodiments. However, otherembodiments that depart from these specific details may also exist.

Embodiments are described herein by way of reference to particularexample scenarios. Particular aspects are described in a non-limitinggeneral context in relation to a an LTE system. However, it should benoted that the embodiments may also be applied to other types ofwireless communication systems and Radio Access Technologies (RAT)supporting positioning such as GSM, UMTS, LTE-Advanced, cdma2000, WiMAX,and WiFi, as well as multi-RAT systems. Furthermore, the signalingdescribed in the disclosure may be either via direct links or logicallinks, e.g. via higher layer protocols and/or via one or more networknodes. For example, the signaling of positioning results between theE-SMLC and the PSAP in LTE is done via multiple nodes comprising atleast the MME and the GMLC.

Although the description of the example scenarios mainly mentionspositioning of UEs, it should be understood that the UE is anon-limiting term which means any wireless device or node such as a PDA,laptop, mobile, sensor, relay, or even a small BS that is beingpositioned, i.e. an LCS target in general. Furthermore, a positioningnode described in different embodiments is a node with positioningfunctionality. For LTE it may be understood as a positioning platform inthe user plane such as the SLP, or a positioning node in the controlplane such as the E-SMLC. SLP may also consist of SLC and SPC, where SPCmay also have a proprietary interface with E-SMLC.

In the description, first positioning result, second positioning result,and third positioning results are used in several places as generalterms to refer to a first area, a second area and a third area,respectively, where the area shall be understood as a formalizeddescription of a geographical area, i.e. in a broader sense than a finalpositioning result. It may e.g. be an intermediate result of apositioning process, an area corresponding to a cell descriptionprovided by an O&M system, or a boundary of a cluster extracted from anAECID database.

A polygon format is described by a list of 3-15 latitude, longitudecorners, encoded in World Geodetic System (WGS) 84 co-ordinates.Currently, uncertainty information for the polygon format is includedimplicitly. No confidence may be reported with the polygon. However, thepolygon is typically pre-determined in a cell planning step whichdescribes the cell area with a certain confidence. The confidence is theprobability that the terminal is actually located within the reportedarea, in this case bounded by the cell polygon.

For e.g. AECID, polygon fusion or merging operations, and polygon ormeasurement cluster splitting operations have been defined foroperations on polygons. Splitting operations are defined for thesplitting of a cluster of high precision position measurement intomultiple smaller clusters. In this way multiple polygons correspondingto the original cluster are created for each tag. The multiple polygonsfor a tag taken together covers a smaller area than a single polygonwould. This may be useful e.g. when doing a position estimation frommultiple results such as multiple positioning methods, or when thereporting of multiple shapes is possible. Geographically distinct areas,areas in hilly terrain, and separate coverage areas of cells in front ofand behind an antenna are examples of areas where splitting may beuseful. Fusion or merging of at least two sub-polygons may be used formerging geographically non-overlapping polygons of sub-clusters to onepolygon, representing all or a subset of said sub-clusters. It may alsobe used for merging overlapping polygons of sub-clusters to one polygon,representing all or a sub-set of said sub-clusters. The fusionfunctionality may be needed when a splitting step is first applied toimprove accuracy, but where reporting of multiple areas or polygons isnot supported.

Seven position reporting formats, each associated with a GeographicalArea Description (GAD) shape, are supported in 3GPP for LTE, UMTS andGSM. All formats may be used for positioning, although some formats maybe more typical for some methods. The seven supported formats are:polygon, ellipsoid arc, ellipsoid point, ellipsoid point withuncertainty circle, ellipsoid point with uncertainty ellipse, ellipsoidpoint with altitude, ellipsoid point with altitude, and uncertaintyellipsoid. Next, typical formats for different positioning methods aregiven.

For CID, the cell boundary is typically modeled by a set ofnon-intersecting polygon segments connecting all the corners of apolygon. For E-CID, the positioning result of CID and TA is typically anellipsoid arc describing the intersection between a polygon and circlecorresponding to the TA. A typical result format of the signal-strengthbased E-CID positioning is a polygon since the signal strength issubject e.g. to fading effects and therefore often does not scaleexactly with the distance. A typical result of AoA and TA positioning isan ellipsoid arc which is an intersection of a sector limited by AoAmeasurements and a circle from the round trip time like measurements.For RF fingerprinting a typical result format is a polygon. Some vendorsalso use a point with uncertainty circle, rendering a very low value ofthe confidence. For AECID a typical result format is a polygon. ForTDOA- or TOA-based methods a typical format of a positioning result isan ellipsoid point with or without altitude, and with an uncertaintycircle, ellipse, or ellipsoid which is the result of intersection ofmultiple hyperbolas/hyperbolic arcs (e.g. OTDOA) or circles/arcs (e.g.UTDOA, GNSS, or A-GNSS). For hybrid positioning, the position result maybe any shape, since the hybrid technique involves a mix of any of themethods above. However, in many cases a typical format is a polygon or apoint with an uncertainty measure. For civic address based positioningthe result may be converted to one of the standardized formats for GADshapes, and is most likely a polygon. Even though some formats may bemore specific for some methods, shape conversion may be used totransform a positioning result from one format or shape to another.

A non-limiting aspect of the disclosure relates to methods that enhancethe applicability and performance of fingerprinting positioning methodsand positioning methods based on CIDs, and in particular that enhancethe performance of the AECID fingerprinting positioning method. A numberof problems have been identified with conventional solutions:

-   -   There is no positioning functionality that exploits restricted        location areas of various kinds, such as CSG cells and        heterogeneous networks with overlapping structures. With CSG        cells in the macro deployment area, different cell reselection        rules apply for different users, and the potential location area        corresponding to the serving macro cell should be different for        users that belong to the CSG and that do not belong to the CSG.        It is not possible to take this into account with the        conventional positioning solutions, which may make conventional        positioning algorithms inaccurate or even failing.    -   With the current 3GPP positioning formats, there is no method        for describing areas where the UE location is unlikely, when the        area is a closed area inside the area where the UE location is        likely.    -   There are no algorithms available for handling of areas that        partly overlap.    -   There are no algorithms that allow for excluding or subtracting        restricted areas from a positioning result, such as areas inside        other areas where users cannot be located, which is a situation        that occurs in heterogeneous networks. Algorithms that may        handle this within existing reporting standards are not known.        As an example, there is no polygon subtraction operation defined        for the polygon position reporting format, e.g. in the AECID        method.    -   There is no signaling that enable signaling of location areas        where the UE cannot be located. The conventional signaling does        not allow for signaling of any area to be subtracted and the        behavior of the nodes and devices receiving such information is        not defined. Such a possibility would enhance the position        reporting and the final accuracy of the received position        result. As an example, a coverage area of a cell may be        described by a first polygon, with a second polygon inside the        first polygon corresponding to an area where the UE cannot be        located. The only possibility with the conventional signaling in        this example is to signal the first polygon.    -   There is no standardized signaling available for signaling of        multiple areas that overlap partly in existing standards, for        example for LTE, UMTS and GSM.

The present disclosure comprises at least the following aspects toaddress the above and other issues:

-   -   Positioning methods accounting for restricted areas and        overlapping areas that occur e.g. for CSG cells and in        heterogeneous networks;    -   Algorithms that transform two areas, one being in the interior        of the other, to a standardized 3GPP reporting format;    -   Device, apparatus, and/or system for signaling of multiple,        overlapping areas, particularly for the LTE network;    -   Device, apparatus, and/or system for signaling of restricted        areas as a part of the positioning result;    -   Device and node behavior to enable handling of location areas        where the UE is not located; and    -   Device and node capability that may be exchanged with other        nodes or devices or may be signaled on request.

Some details regarding the problems addressed in this disclosure areillustrated by the following three non-limiting examples. There may besituations when more than one of the example situations applies in thesame network.

Example 1 CSG Cells

If the coverage area of a CSG cell is within the coverage area of amacro cell, the coverage area of the CSG cell may or may not be a partof the area associated with the serving macro cell reported based on thecell ID. If it is part of the area depends on whether the UE belongs tothe CSG or not. The example is illustrated in FIG. 2, where the cellcoverage area shapes are schematically illustrated. Cell1(1) of BS1 is aCSG cell to which UE1 and UE3 are able to reselect, whilst UE2 is notsubscribed to the CSG and cannot be served by BS1. UE2 is thus served byBS2 even in the close proximity to BS1. If the coverage area of Cell1(1)is described by a closed geographical area A1, and A2 denotes thecoverage area of Cell1(2), A2\A1 is the area of A2, excluding the partoverlapping with A1. The positioning result based on the serving cellidentity for a UE located within the area A2 may thus be given by oneof:

-   -   A1 for UEs that are served by Cell1(1);    -   A2\A1 for UEs that are served by Cell1(2) but may also be served        by Cell1(1);    -   A2 for UEs that are served by Cell1(2) and cannot be served by        Cell1(1).

In the above and also further in the disclosure, the sign ‘\’ usedbetween two geographical areas such as A1 and A2 is used to denote areasubtraction. A similar situation as the one described above may occurwhen the radio network infrastructure is shared by multiple operatorsand not all the radio nodes are available to all operators. As aconsequence, not all UEs may be able to access all radio nodes.

Example 2 Time-Dependent Cell Coverage

In this second example illustrated in FIG. 3, the activity of some cellsvaries in time and thus the neighbor cell area description also variesin time, depending on the activity of neighbor cells. The varyingactivity may in one example mean that some cells are turned ON/OFFduring certain times of the day or week when the traffic load in thenetwork is low (e.g. during the close times of a supermarket or ashopping center). The purpose may for example be to save energy. FIG. 3a illustrates that the UE is served by Cell1(1) of BS1 at times when thecell is active, and FIG. 3 b illustrates that the UE is served byCell1(2) of BS2 when BS1 and Cell1(1) is inactive. The serving area ofCell1(2) is thus different in FIG. 3 a and FIG. 3 b, depending onwhether BS1 is active or not.

Example 3 Geographical Area with Restriction Access Provided On-Line

The flexibility of a positioning system and its ability to learn aboutthe environment and adopt accordingly are very valuable properties thatmay significantly minimize the network operator's efforts. Areas withrestricted access may be configured with the conventional positioningsolutions. However, they are typically configured statically and mayrequire a lot of non-automated work and reconfiguration of more than onecell, such as descriptions of the coverage area of multiple neighborcells, which are tedious tasks often subject to human mistakes.

Several non-limiting examples of areas with restricted access, or inother words areas where the UE location is unlikely, have been given inthe previous sections. Such areas are further referred in the currentdisclosure to as black areas. A black area is thus a predefinedgeographical area for which a probability that the LCS target is locatedwithin the predefined geographical area is below a threshold. In otherwords, the probability that the LCS target is located within the blackarea is low. The black area could for example be a geographical areawith physically restricted access or with the access restricted in termsof the radio connection, e.g., to a network or a cell. In someembodiments, the term black area may also relate to areas with no orinsufficient positioning measurements. How low the probability is maydiffer for different types of black areas. The probability shouldtypically be around 1% or lower in the case of a physically restrictedaccess area. The probability or the value of the threshold used fordetermining the probability is not important to reach the object of thedisclosure, but is rather just a way to describe the definition of ablack area.

In a more general sense, a black area may be defined as a geographicalarea, in one dimension such as in the vertical domain only, in twodimensions such as in the horizontal domain, or three dimensions such asin the horizontal and vertical domains. In case of a one dimensionalarea in the vertical domain, a UE would be restricted between a lowerand an upper altitude, e.g. between 150 m and 350 m in a cell covering ahigh building. The two-dimensional case in the horizontal domain, is the“normal” case used for all the figures of the application. The threedimensional domain corresponds to a definition of the black area as arestricted volume, which may be useful in cities where athree-dimensional cell planning is needed, such as in Hong-Kong. Theblack area may e.g. be a geographical area with:

-   -   A restricted radio access, the restricted access being described        by a subscriber group which defines the access rights for a        radio node, a certain service, or a certain radio bearer type.        CSG cells is one specific example of the restricted radio        access;    -   A restricted physical access, such as areas where the UEs are        not expected to be located, due to e.g. the physical terrain        such as mountains or lakes, or due to constructions or public        access restrictions;    -   No or insufficient fingerprint information. If little        information is available that means that very few UEs have been        in that area. Therefore an area with no or little information        may be artificially modeled as a black area. Such an area may        also be referred to as an area where an amount of measurements        with location information is below a threshold. When such an        area is significant in size, there is currently no way to        describe it as a cluster. Describing an area with no        fingerprinting information as a black area may improve the        accuracy of positioning results;    -   A property that it is describing an overlap of two or more        location areas. One example is a handover region, i.e. an        overlap of multiple cell areas. This information may be used        when it is known that a UE is within a first cell area but does        not hear one or more of the other cells, as this implies the        exclusion of the cell overlap areas from the first cell area        description. Another example is an overlapping area of two or        more location areas. An area describing the overlap may be        signaled separately to reduce signaling overhead. This is only        possible if more than one location area may be signaled. A third        example is an overlapping area which may be signaled as a part        of one location area and subtracted from another location area,        e.g. to reduce signaling overhead or to increase the accuracy of        the location information. Also in this case signaling of        multiple location areas may be needed.

The black area applicability may be UE-specific, UE-group specific orcommon for all UEs. As an example a cell description with physicalaccess restriction is common for all UEs in the area. The applicabilitymay also be conditional, e.g. only applicable when a UE is served by acell overlapping with the black area. Furthermore, it may betime-dependent, e.g. depending on the activity of some cells asdescribed in Example 2 above. In this case a certain time may be viewedas another condition.

A black area may be associated with another geographical area or cell.The association may be done via e.g. tracking area identification. Inone example, the black area is associated with one or more cells withwhich it has at least partial overlap. Another possibility is that theblack area is associated with the serving cell of a UE.

In embodiments, an LCS server, which may be a positioning node, obtainsinformation relating to a first predefined geographical area which is ablack area, and then uses this information when performing positioningof an LCS target, which may be a UE.

The information relating to a black area may be obtained in differentways. In one embodiment it may be provided to the LCS server manually,by an information storage device, by a software program, or by input viaa graphical interface. In another embodiment it may be signaled, eithertogether with (i.e. in the same message) or without another geographicalarea or cell to which the black area is associated. In still anotherembodiment it may be signaled either with (i.e. in the same message) orwithout an intermediate positioning result. The intermediate positioningresult may be a geographical area from which the black area has not yetbeen subtracted. Any of the embodiments for obtaining the informationrelating to black areas may be combined with each other.

In a further embodiment, the black area information may be stored in amemory or a database e.g. in the UE or in the positioning node, and thenretrieved from the database when a positioning of the UE is requested.

The information relating to the black areas may in embodiments be usedto modify the description of other areas, such as the areas with openaccess or cell area descriptions, which do not necessarily representpositioning results. This may be done statically, semi-statically ordynamically.

The information may also, or alternatively, be used to adjust thepositioning result by excluding the black areas. A specific example ofthe positioning result is one or more of an AECID result, a CID result,an E-CID result, and a hybrid positioning method result. The adjustmentof the positioning result may e.g. be done in the LCS server, in the LCStarget, or in the LCS Client, e.g. the PSAP, depending on where theblack area information is available.

To enable the using of black areas for positioning, at least one of thefollowing is defined:

-   -   Black area modeling and presentation formats;    -   Signaling means and interfaces;    -   Nodes behavior for interpreting the black area information. As        an example, a new LCS target or LCS Client behavior is needed to        correctly interpret the received black area information, i.e. as        the area where the LCS target may not be located;    -   Applicability rules and triggers associated with black areas;    -   Methods for operating black areas, such as methods for the area        subtraction operation, which may be used for adjusting        positioning results.

Black Area Modeling and Formats:

In principle, a black area may be described in a way similar to thatused for describing a UE location area. In one embodiment, a black areamay be described by means of any of the conventional position reportingformats, e.g. GAD shapes. In a specific example, a black area may bedescribed by a polygon. There is no standardized way for describing alocation area with multiple GAD shapes. A similar approach, i.e.describing an area with two or more not necessarily the same GAD shapes,may also be adapted in one embodiment of the current disclosure fordescribing a black area. A black area may also be described with a civicaddress or its part (example: “6th floor”).

The format of the black area description may or may not be the same asthe format of the associated area. The black area information may alsocomprise uncertainty and a confidence level. In one embodiment, whensignaled together with an associated area or a positioning result, theblack area has the same confidence level as the associated area and thepositioning result.

In one embodiment, the black area information is modeled and presentedseparately from other area(s), e.g. as described above. To enableexplicit signaling of the black area information, new signaling isproposed. There are also methods of incorporating the black areainformation that allow avoiding explicit signaling of black areas. Twosuch methods are described below. The first method, the extendedboundary method, may be used with the currently standardized signaling,but have some limitations. The second method, the area splitting method,relies on the possibility of signaling multiple GAD shapes for a singlelocation area. The two methods are described for an inner black areascenario, but adapting them to a scenario with the black area partiallyoverlapping with the associated area is straightforward and is thus notfurther described.

Method 1. The extended boundary method for describing an inner area withrestricted access: The method disclosed in this section enablesaccounting for an inner black area using the currently standardizedpositioning formats and produces a single extended boundary of an areaout of the two boundaries which are the outer boundary of the locationarea and the boundary of the black area with restricted access. Themethod does not require new signaling and does not require any extensiveimplementation. This may be a good solution for the cases when thestandard formats are not limiting, such as a case when the maximumnumber of vertexes of a resulting polygon does not exceed 15. 15vertexes is the limit in the current standard.

An outer boundary of the area A1 where the UE may be located, e.g. basedon the cell ID, is described by a first geometrical shape. A boundary ofan inner area denoted A2 where the UE may not be located, i.e. the blackarea, is described by a second geometrical shape. A non-limiting examplewhere the first and the second shapes are polygons is illustrated inFIG. 4 a. In the FIG. 4 a, the boundary of A1 may be given e.g. by asequence of points <p1, p2, p3, p4, p5, p6, p7>. The method 1 comprisesthe following steps:

-   -   1. Define additional vertex(es) for A2. If the boundary of A2        contains at least one vertex (e.g. being described by a        polygon), add an additional vertex close to an existing vertex        of the said boundary of A2. If the boundary of A2 contains no        vertexes (e.g. being described by an ellipse), add two        additional vertexes close to each other on the said boundary of        A2. It may differ how close the vertexes should be, depending on        the size of the areas e.g.    -   2. Define additional vertex(es) for A1. If the boundary of A1        contains at least one vertex (e.g. being described by a        polygon), add an additional vertex close to a vertex of the said        boundary of A1. If the boundary of A1 contains no vertexes (e.g.        being described by an ellipse), add two additional vertexes        close to each other on the said boundary of A1.    -   3. Two vertexes close to each other are now available for A1 and        another two vertexes close to each other are available for A2.        Connect one of the additional vertexes of A1 to one of the        additional vertexes of A2, and connect the second of the        additional vertexes of A1 to the second of the additional        vertexes of A2, e.g. with two non-intersecting lines as        illustrated in FIG. 4 b.    -   4. The area where the UE may be located may now be described by        a boundary extended to include both the boundary of A1 and the        boundary of A2. In FIG. 4 b, the extended boundary may be given        e.g. by the sequence of vertexes <p1, p2, p3, p4, p5, p6, p7,        s1, s2, s3, s4, s5, s6, s7, p8>.

Variations of this algorithm may also be envisioned, e.g. no additionalvertexes (such as p8 and s7 in FIG. 4 b) may be added, but instead thetwo boundary area may be just connected to each other. Using thenotation in FIG. 4 b, the extended boundary may be given in this case bythe sequence of vertexes <p1, p2, p3, p4, p5, p6, p7, s1, s2, s3, s4,s5, s6, s1, p7>. This is a possible solution, although some conventionalalgorithms may not be able to correctly deal with repeating edges in apolygon shape.

Another slight variation of the algorithm may be envisioned e.g. for acase when the boundary of A1 and the boundary of A2 have at least onecommon vertex, but since extending the algorithm for such cases isstraightforward, it is not described further.

Method 2. The area splitting method to enable describing an inner areawith restricted access: Unlike the extended boundary method, the methoddescribed in this section relies on a possibility to describe an areawith multiple shapes but allows avoiding the format limitation (e.g. thelimit of maximum 15 vertexes). The idea of this method is that when aninner area with restricted access is identified, the area surroundingthe said inner area is split into at least two areas. The methodcomprises connecting the boundaries of the two areas in two or moreplaces such that area A1 splits into two or more shapes. The connectingmay be implemented with or without adding extra vertexes as e.g.illustrated in FIGS. 4 c and 4 d, respectively. In FIG. 4 c, theboundaries of the new areas may be given by the two correspondingsequences of vertexes: <p1, p2, p3, p4, s5, s6, s1, p7> and <s1, s2, s3,s4, s5, p4, p5, p6, p7>. If the standard would allow signaling ofmultiple shapes, these two polygons could further be signaled e.g. tothe LCS target/UE or the LCS Client.

Signaling Means and Interfaces:

The disclosed signaling comprises:

-   -   Signaling of the black area information. Some signaling method        alternatives are disclosed below. The black area information        comprises at least a description of a geographical area        corresponding to the black area. The black area information may        also include the uncertainty and the confidence information. The        black area description may follow the formats discussed above,        and may e.g. be described as a polygon. In the following list,        the signaling is via direct links, via higher layer protocols,        and/or via one or more network nodes. For the signaling between        E-SMLC and PSAP, the positioning result is transferred via        multiple nodes e.g. The black area information may in        embodiments be signaled between:        -   The LCS server and the LCS target in general, e.g. via the            LPP. The two nodes may be any of a wireless device, a            network node or a radio node.        -   The LCS server and the LCS Client (e.g., between E-SMLC and            PSAP, between SLP and External LCS Client, between E-SMLC            and eNodeB, or between E-SMLC and UE).        -   The positioning node (e.g., E-SMLC or SLP) and other network            node (e.g., MME/MSC/GMLC/O&M/SON/home eNodeB),        -   The positioning node and a radio node, where the radio node            is e.g., an eNodeB or a beacon device. The signaling may in            this case be via LPPa.        -   The user plane positioning node (e.g., SLP in LTE or other            RAN) and the control plane positioning node (e.g., E-SCML in            LTE).        -   Different radio nodes (e.g., between different eNodeBs,            between different Location Measurement Units (LMU), between            eNodeB and LMU).        -   Radio network nodes and radio nodes (e.g. between Radio            Network Controller (RNC) and NodeB in WCDMA).        -   UE and radio node, e.g., via a RRC protocol.    -   Signaling of the capability of handling black areas. In the        above, it is assumed that the involved nodes or devices (e.g., a        UE) also get a capability of dealing with the enhanced location        area description. Such a capability implies support of the        corresponding interface that enables the described signaling and        may also imply a certain behavior (e.g. interpreting the black        area information differently from the conventional location area        information, e.g. as the area where the LCS target is not        located). This capability may be optional and the capability        information may be exchanged or sent upon a request from other        nodes (e.g. LCS server which may be E-SMLC in LTE) or devices.        Similarly, the LCS server may also have a formal capability of        dealing with restricted areas, in addition to the conventional        functionality.    -   Signaling of the positioning result adjusted to account for the        black area information. This section implies no explicit        signaling of the black area information, but rather the result        of accounting for it, e.g., after applying the extended boundary        method 1, or the area splitting method 2 described in this        disclosure. The signaling means may thus be the same as for        signaling of a positioning result without accounting the black        area information.    -   Signaling of the information enabling the applicability rules        and triggers associated with black areas. The positioning node        needs to be made aware of the UE ability to access or get served        in certain areas or in certain cells. In one embodiment, the        ability is the UE subscription information (e.g. to a certain        CSG). Alternatively, the information may be received by the        positioning node (with or without a request from the positioning        node) e.g. from the UE (the UE sends an indicator over LPP),        from another network node (from MME together with the        positioning request sent from MME to the positioning node or in        response to a request message sent by the positioning node to        MME; or from a femto gateway or from GMLC, a Home Location        Register (HLR), or a Home Subscriber Service (HSS)), or from a        radio network node (e.g., from eNodeB in LTE via LPPa or from        RNC in WCDMA). Another alternative is that the positioning node        may request the UE subscription information e.g. when there are        CSG cells in the potential location area. The positioning node        needs also to be made aware of the radio nodes activity. In one        embodiment, a radio node (e.g. eNodeBs or home eNodeBs) notifies        the positioning node about its activity/inactivity (e.g. via an        indicator sent via LPPa protocol). This may serve as an        indicator to the positioning node about e.g. which cell area        descriptions in the area shall apply when cell ID-based        positioning is used. In another embodiment, the positioning node        is provided the activity information by another network node        (e.g. SON or O&M node).

Methods of Signaling the Black Area Information

The disclosed subject matter is not limited to the example alternativesdescribed hereinafter:

Signaling Alternative 1: The current alternative comprises signaling ofat least two types of positioning results, where the first positioningresult is one or more of a conventional positioning result and at leastone of the second positioning results describes at least one black area,any format may be used for a second positioning result, and the formatmay not necessarily be the same for the first positioning result and thesecond positioning results, and may not necessarily be the same for allof the second positioning results. In one embodiment, at least one ofthe second positioning results is described by a polygon. In anotherembodiment, all first positioning results are signaled as one structure,and all second positioning results are signaled as another structure inthe same message, as in the following example:

positioningResults={positioningResult1, positioningResult2, . . . }blackAreaResults={blackAreaResult1, blackAreaResult2, . . . }

In another embodiment, the structure applies only to the black areainformation, as in the following example:

positioningResultblackAreaResults={blackAreaResult1, blackAreaResult2, . . . }

In yet another embodiment, only one black area may be signaled in onemessage, as in the following example:

positioningResultblackAreaResult

In yet another embodiment, multiple positioning results may be allowedin the same message and the same information element may be used for thefirst positioning results and the second positioning results. Anindicator may be used to indicate whether a positioning result describesa black area or not. The indicator may be an optional Boolean indicatorsignaled with value ‘True’ for each of the second positioning result.For example:

positioningResultpositioningResult, blackArea=true

Signaling of the black area information may be directed to one or moredestinations. The broadcast/multicast of this information may be e.g.via RRC signaling directed to two or more UEs in the coverage area ofthe cell, or via LPP. With multicast signaling, a condition may be usedin the signaling node, which may be the positioning server or the radionode, to select a subset of receiving devices or nodes. In anotherembodiment, a condition indicating when the signaled second positioningresult shall be interpreted as a black area may also be signaledtogether the second positioning result. For example:

blackAreaResult, blackAreaCondition=(UE does not belong to CSG <CSG>)

The advantage with signaling the condition is that the information maybe signaled, without association with a specific wireless device, tomore than one wireless device or to another network node (e.g., radio BSor another positioning node or MME), which then may use the black areainformation selectively, applying the condition.

Signaling Alternative 2: The embodiments in this alternative coversignaling of a positioning result and its overlap with at least oneblack area. The embodiments described for Signaling Alternative 1 applyalso in this section with second positioning results being overlap areaswith the corresponding first positioning results. The number of secondpositioning results shall either be the same as the number of firstpositioning results in the same message, or the relation between thefirst and second positioning results shall be clearly defined, e.g., byindexes or separate structures for each combination of the first resultand the corresponding second positioning result if any. Alternativelythe number of first positioning results shall be one.

Signaling Alternative 3: The embodiments in this alternative 3 coversignaling of black area information separately from the firstpositioning result. The embodiments described for Signaling Alternative1 apply also in this section with the set of first positioning resultsbeing empty. In some embodiments, there may be no need to indicatewhether this is the information related to black areas or not sincethere is no first positioning results in the same message and thus noneed to distinguish. However, it then needs to be known to the receivingside that the message contains only the black area information.

Signaling Alternative 4: Vector graphics may be used for signaling theblack area information or the positioning result after accounting forthe black area information, which makes it possible to avoid theposition reporting format constraints in the current standard. Vectorgraphics is a standardized way of signaling and displaying simplegraphics, like geometrical geographical shapes, within a short messageservice format.

Hereinafter, the method for building up the black area informationdatabase and for utilizing the black information for positioning isdescribed according to embodiments. The described steps are an examplealgorithm flow, and variations such as excluding or making optional someof the steps, changing the order of the steps, or performing some stepsmore often than other steps may be envisioned. Steps 1 and 2 below maye.g. be performed only when new data is available, whilst Step 6 may beperformed within a positioning session.

-   -   1. Build up a geographical database of coverage area        descriptions, while allowing for storing high-precision        positions with fingerprints describing black areas, e.g., for        CSG cells, and/or geographical areas describing black areas        without fingerprints, e.g., by entering manually a        geographically restricted area or collecting high-precision        positions along the perimeter of the restricted area. This is        done such that the system is capable of extracting the black        area information on demand, which may be e.g. user-dependent        and/or time-frequency dependent. Black area clusters describing        areas with no or insufficient fingerprints may also be created        and stored or created dynamically specifically for a certain        area.    -   2. Build black area clusters of high precision positions. In one        embodiment, the black area cluster boundaries (typically        polygons) are obtained for a given confidence level, where the        interpretation of the confidence level may be the same as for        GAD shapes, including polygon, used in the AECID positioning        method.    -   3. The black area information may be exchanged among the nodes        statically, semi-statically or dynamically, e.g. between radio        nodes such as eNodeBs, between the positioning node and a radio        node, between the positioning node and other network nodes such        as O&M nodes or MME, or between positioning nodes, e.g., between        SLP and E-SMLC.    -   4. Associate at least one location area with at least one black        area e.g. by means of tagging such as adding a cell ID of the        associated cell. For each black area an associated area is found        and is assigned the corresponding tag. An associated area may be        the area described by a cluster or cluster boundary        intersecting, i.e. having a non-empty overlapping area,        excluding the cluster boundary, with the cluster describing the        black area. The intersection may be found by a conventional        algorithm and may be obtained statically and stored in the        internal or external memory. It may also be obtained        dynamically.    -   5. For a given associated location area, execute at least one of        extraction of at least one black area (e.g. using the tag) and        find the overlap (if not yet known), and extraction of the        overlap of the associated location area with at least one black        area.    -   6. When the handling of black areas is enabled or triggered        (e.g. a certain location area is associated with one or more        black areas corresponding to CSG cells and the location area is        a serving macro cell of a UE being positioned), either of the        following may occur:        -   a. The positioning result may be adjusted in a network node            (e.g. the positioning node) to account for at least one            black area, where the positioning result may further be            signaled to a wireless device, an LCS Client, another            network node, or a radio node;        -   b. The positioning result before subtracting the black areas            and the black area information are signaled (refer to            Signaling Alternatives 1 and 4 for more details) to at least            the positioning target or the LCS Client, so that the            receiving side may use the obtained black area information            to adjust the positioning result;        -   c. The positioning result and its overlap with at least one            black area are signaled (refer to Signaling Alternatives 2            and 4 for more details) to at least the positioning target            or the LCS Client, so that the receiving side may use the            obtained black area information to adjust the positioning            result;        -   d. The black area information is signaled (refer to            Signaling Alternatives 3 and 4 for more details) by a            network or radio node to a UE, so that the UE may use the            obtained black area information to adjust the positioning            result obtained by the UE (e.g. in UE-based positioning).    -   7. The adjustment of a positioning result to account for a black        area comprises subtracting the black area from the location        area, where the subtracting may be e.g. implemented using the        subtracting algorithm described in this disclosure. The adjusted        positioning result is further used for positioning the LCS        target.

Shape conversion may also be applied, e.g. prior to signaling thepositioning result. Shape conversion is a transformation betweengeographical positioning formats that usually cause a loss of accuracy.In one embodiment, the available black area information is accounted forin shape conversions. In a separate embodiment, shape conversion may beapplied separately but consistently to the location area and black area.In another embodiment, shape conversion is applied to the result ofsubtracting the black area. The shape conversion may, for example, beused in Step 6a, e.g. in E-SMLC prior signaling to the LCS Client or LCStarget.

In the following section, an example subtracting algorithm foradjustment of a location area accounting for a black area is disclosed.The algorithm may be applied at any node or device that may obtain afirst positioning result and a second positioning result. The algorithmis described for two areas, but extending the functionality for handlingmultiple areas (an overlap of multiple areas or subtracting the overlapfrom multiple areas) is straightforward.

-   -   1. Acquire a first positioning result (area A1). The way of        acquiring depends on the node implementing these steps, e.g. may        be received via signaling or acquired from a database or memory        or delivered by another functional block.    -   2. Acquire a second positioning result (area A2), which may        potentially overlap with the said first positioning result,        selected e.g. by the tag corresponding to the first positioning        result. The way of acquiring depends on the node implementing        these steps, e.g. may be received via signaling or acquired from        a database or memory or delivered by another functional block.    -   3. Find the adjusted positioning result, further referred to as        the third positioning result, using the following steps.        -   a. Find the overlap area of the said first positioning            result and the second positioning result, i.e. A1∩A2 where ∩            means intersection. Any conventional overlap detection            algorithm may be used. In some described embodiments the            overlap is given, e.g. via signaling, and this Step 3a may            be skipped.        -   b. Find the third positioning result, i.e. A1\(A1∩A2). The            third positioning result may also be delivered by one of the            two area subtraction algorithms described below.    -   4. The adjusted positioning result may further be        fitted/converted into one of the pre-defined formats, e.g. if it        is to be signaled to the positioning target or other node and        the allowed signaling format allows for signaling the obtained        third result (see Section 3.2.1 and Section 3.2.2 for more        details).

Area Subtraction Algorithms

The following situations may occur:

-   -   a) The second positioning result is fully covered by the first        positioning result, A1∩A2=A2. If the intersection of A1 and A2        equals A2, then A1 must at last cover A2, i.e. A1 includes A2        and possible more.    -   b) The first and the second positioning result partially        overlap, i.e. (A1∩A2)⊂A2 and (A1∩A2)⊂A1. In this case the        intersection of A1 and A2 are contained both in A1 and A2, hence        the intersection is an overlap.    -   c) The first and the second positioning result do not overlap        (the overlap area is empty, i.e. A1∩A2=Ø);    -   d) The first positioning result is fully covered by the second        positioning result, A1∩A2=A1.

The subtraction algorithms described further in this section find outwhich situation applies and return the result of A1\(A1∩A2) whenrelevant. The result is non-empty set in the situations a, b and cdescribed above.

When the situation d occurs, the result is an empty set, which mayhappen, e.g. for the following reasons in the case of fingerprintingpositioning such as AECID positioning:

-   -   The clusters are typically built for a confidence level below        100%, so some positions may still occur beyond the created        cluster boundaries e.g. due to fading effects;    -   The database is corrupt or outdated (e.g., due to cell        reconfiguration such as changed antenna configuration comprising        tilt, azimuth and/or height, newly introduced sites, changed        maximum BS transmit power, new constructions that impacts signal        propagation paths, etc.).    -   The database is not yet fully populated.

When the situation d occurs, the positioning system may take one or moreof the following actions:

-   -   Report a positioning result as the area of A1 or a larger area        of A1 corresponding to a higher confidence level (preferred        solution), or A2 as a positioning result (since the UE location        is even beyond the A2 area), or a positioning failure;    -   Trigger a more accurate positioning method (e.g.        OTDOA)—preferred solution when more positioning attempts are        acceptable;    -   Collect the occurrence statistics of such cases (e.g. by cell        IDs, or cluster tags);    -   Increase the confidence level when creating cluster boundaries,        when the rate of occurrences of such cases is above a threshold;    -   Indicate the need and/or trigger clean up, update or rebuild of        the fingerprint or cluster database or its part(s) when the rate        of occurrences of such cases is above a threshold;    -   Trigger collecting measurements in the area, e.g. by configuring        one or mode network nodes or devices reporting measurements with        the location information e.g. for the purpose of minimizing        drive tests or for the purpose of populating the fingerprinting        database if such a possibility exists.

Example subtraction algorithm 1: It is assumed that the cluster ofmeasurements corresponding to A1 is available and the boundary of areaA2 is available. This may be the case, e.g., when the intersectiondetection is performed in the positioning server. In case when only theboundary of A1, but not the cluster of measurements, is available, anartificial cluster of interior may be created in order to make thealgorithm applicable. The output is the boolean isOverlapping and theresult of A1\(A1∩A2) when isOverlapping=true. Steps 1 and 2 are executedonce per each black area A2 if multiple black areas are present.

-   -   1. Identify a subset of clustered points inside A1 that are also        inside or at the boundary of A2. For example, a check for each        of the points of A1 may be performed to find out whether the        point is inside A2. The check procedure may be implemented e.g.        as a standard test ray technique. If the subset is empty, set        isOverlapping=false and return the result (e.g.        A1\(A1∩A2)=A1\Ø=A1), otherwise set isOverlapping=true and        proceed to the next step.    -   2. Virtually remove, e.g. by marking, from A1 all the points        that are in the subset, i.e. covered by A2.    -   3. For a given confidence level, rebuild the cluster        descriptor(s) of A1 with the said virtually removed points        excluded. The third positioning result is given by the result of        this operation.

The example A1 cluster, A2 boundary and the result of virtual removingof A1 measurement points inside of A2 are illustrated in FIG. 4 e.

Example subtraction algorithm 2: It is assumed that the boundaries ofboth A1 and A2 are available. This may be the case, e.g., when thealgorithm is executed in the positioning server or the first and thesecond positioning results are signaled to the positioning target or theLCS Client. If no boundary is available, but only cluster(s) ofmeasurements, then the algorithm described in this section is precededby creating the cluster boundaries, e.g. by conventional polygonbuilding algorithms used in AECID. The output is the booleanisOverlapping and the result of A1\(A1∩A2) when isOverlapping=true.Steps 1-2 are executed once per each black area A2, if multiple blackareas A2 are given as input.

-   -   1. Find the overlap of A1 and A2, i.e. the result of A1∩A2. This        may be done e.g. by a conventional algorithm such as a test ray        technique. If the result is an empty set isOverlapping=false,        otherwise set isOverlapping=true.    -   2. If the result of A1∩A2 is trivial, e.g. it is an empty set or        A1, the boundary of the third positioning result is given by A1        or the empty set, respectively. If the intersection result is A2        or a part of A2, the new boundary of the third positioning        result has to be found, where the new boundary shall satisfy the        following rules:        -   a. The boundary of the third positioning result consists of            the boundary of A1, except the A1 boundary parts that are            strictly inside A2, and        -   b. The boundary of the third positioning result contains the            parts of the A2 boundary which are strictly inside A1, and        -   c. The parts of the A1 boundary that touch from outside the            A2 boundary. See e.g. the line between points p1 and p2 in            FIG. 4 f, where the result area A1\(A1∩A2) is the area with            stripes.

From the three rules above it automatically follows that the parts ofthe A1 boundary that touch the A2 boundary (see e.g. the line betweenpoints p3 and p4 in FIG. 4 f) from the inside are not included in theboundary of the third positioning result. The extended boundary methodand the area splitting methods, both described in the currentdisclosure, may be applied to the third positioning result, e.g. whenA1∩A2=A2. It should also be noted that the outer boundary of the thirdpositioning result may comprise multiple disjoint areas, e.g. as in FIG.4 f, even if the outer boundary of A1 comprises one area. If necessary,a polygon fusion algorithm may therefore be applied to the obtainedthird positioning result, e.g., when the signaling of multiple shapes isnot supported.

In one exemplary embodiment, a geographical area with restricted accessis provided to the positioning node, e.g. via a graphical interface. Thepositioning node then converts the marked geographical area to an areadescribed following the format and coordinates, and the positioning nodeuses this information to update its database with area descriptions.

In another exemplary embodiment, the description of, or the informationabout the areas with restricted access that is stored in the databasemay be used to dynamically create or adjust the areas of interest, e.g.by excluding the areas with restricted access from certain clusters. Thestored description of areas with restricted access may also be signaledto or exchanged with other nodes or devices. Alternatively, theinformation stored in a database or some memory, may also be used toupdate the stored description of other areas.

In a further embodiment, certain areas may have restricted public accessand thus may potentially be excluded for commercial positioningservices. However, such areas may still be used as areas of potential UElocation for some specific services, e.g. emergency positioning orsecurity positioning service, or for a certain group of UEs having theaccess to these areas.

FIG. 5 a is a flowchart of a method in an LCS server of a wirelesscommunication system, for positioning of an LCS target, according to anembodiment. In one embodiment the positioning is based on an adaptiveenhanced cell identity method. However, other positioning methods mayalso be used. The method comprises:

-   -   510: Obtaining information relating to a first predefined        geographical area, wherein it has been determined that a        probability that the LCS target is located within the first        predefined geographical area is below a threshold. The first        geographical area is thus a black area. Obtaining the        information may in one embodiment comprise receiving the        information from a network node. However, the information may        also be provided to the LCS server manually, by an information        storage device, by a software program, or by input via a        graphical interface.    -   520: Receiving a request for a positioning of the LCS target.    -   530: Using the obtained information relating to the first        predefined geographical area for the positioning of the LCS        target.

In one embodiment, the method further comprises storing the obtainedinformation relating to the first predefined geographical area in adatabase, and retrieving the stored information based on the receivedrequest. The database may e.g. be in the LCS server.

The information relating to the first predefined geographical area mayin embodiments comprise at least one of the following: a firstpredefined geographical area description; a second geographical areadescription associated with the first predefined geographical area; anda condition for when the first predefined geographical area isapplicable. The second geographical area may for example be a cellassociated with the black area. The first predefined geographical areadescription may in one embodiment be a cluster of measurements withlocation information for LCS targets. Alternatively, the firstpredefined geographical area description may be a polygon determinedbased on the cluster of measurements with location information for LCStargets. The condition for when the first predefined geographical areais applicable may be that a time condition is fulfilled, or it may bethat the LCS target corresponds to a specified LCS target. The example 2described above with reference to FIG. 3 a, is an example of when ablack area is applicable when a certain time condition is fulfilled. Theexample 3 of the CSG cell described with reference to FIG. 2, is anexample where the black area is applicable only when the LCS target is aspecific target, i.e. a UE which has access to the CSG cell.

In embodiments, the first predefined geographical area is at least oneof the following: a physically restricted area; a radio accessrestricted area; an area where an amount of measurements with locationinformation is below a further threshold; and an area describing anoverlap of two or more location areas.

FIG. 5 b-c are flowcharts of the method in the LCS server according toembodiments A and B, where the step of using 530 the obtainedinformation relating to the first predefined geographical area for thepositioning of the LCS target is further detailed. In embodiment A ofFIG. 5 b, using 530 the information relating to the first predefinedgeographical area comprises adjusting 531 a second geographical areadescription associated with the first predefined geographical area basedon the information relating to the first predefined geographical area,and transmitting 532 the adjusted second geographical area descriptionto an LCS client interacting with the LCS server for the positioning ofthe LCS target. The LCS server may thus use the black area informationby adjusting a description of a cell associated with the black area, oradjusting an intermediate positioning result, and then transmit theadjusted area to the LCS client. Alternatively, the LCS server adjuststhe second geographical area, which may be retrieved from the databasedescribed above with reference to FIG. 5 a, and stores the adjustedgeographical area description in the database. In these embodiments, theadjusting 531 may comprise excluding a first predefined geographicalarea description comprised in the information relating to the firstpredefined geographical area from the second geographical areadescription. This may e.g. be done with the region subtractionalgorithms described previously in the disclosure. Alternatively, theadjusting 531 may comprise connecting a boundary of a first predefinedgeographical area description comprised in the information relating tothe first predefined geographical area with a boundary of the secondgeographical area description to form an extended boundary comprisingboth of said boundaries, the extended boundary describing at least onearea excluding the first predefined geographical area. An example ofthis embodiment is described above in Method 1—the extended boundarymethod.

In FIG. 5 b illustrating the flowchart of the method according toembodiment B, using 530 the information relating to the first predefinedgeographical area comprises transmitting 535 the information relating tothe first predefined geographical area to an LCS client interacting withthe LCS server for the positioning of the LCS target. The LCS server maythus in this embodiment B transmit both the black area information andan associated cell or an intermediate positioning result to the LCSclient so that the client may make the adjustment needed instead. In oneembodiment, the transmitted information relating to the first predefinedgeographical area comprises an indicator indicating whether ageographical area description in the transmitted information is a firstpredefined geographical area description. This is to enable the LCSclient to identify if the received information is a black area or not.

FIG. 6 a is a flowchart of a method in an LCS client of a wirelesscommunication system for positioning of an LCS target. The LCS clientmay in one embodiment be co-located with the LCS target. The positioningis managed by an LCS server interacting with the LCS client for thepositioning of the LCS target. The method comprises:

-   -   610: Receiving information relating to a first predefined        geographical area from the LCS server, wherein it has been        determined that a probability that the LCS target is located        within the first predefined geographical area is below a        threshold.    -   620: Using the received information for the positioning of the        LCS target

This is thus the method in the LCS client corresponding to embodiment Bdescribed above for the method in the LCS server. The informationrelating to the first predefined geographical area may comprise at leastone of the following: a first predefined geographical area description;a second geographical area description associated with the firstpredefined geographical area; and a condition for when the firstpredefined geographical area is applicable. The first predefinedgeographical area description may be a cluster of measurements withlocation information for LCS targets. The first predefined geographicalarea description may alternatively be a polygon determined based on thecluster of measurements with location information for LCS targets. Thecondition for when the first predefined geographical area is applicablemay be that a time condition is fulfilled, or that the LCS targetcorresponds to a specified LCS target. Furthermore, the first predefinedgeographical area may be at least one of the following: a physicallyrestricted area; a radio access restricted area; an area where an amountof measurements with location information is below a further threshold;and an area describing an overlap of two or more location areas.

FIG. 6 b is a flowchart of the method in the LCS client according toembodiment B, where the step of using 620 the received information forthe positioning of the LCS target is further detailed. The receivedinformation comprises an indicator indicating whether a geographicalarea description in the received information is a first predefinedgeographical area description, and using 620 the received informationcomprises adjusting 621 a position of the LCS target based on thereceived information. The indicator makes it possible to differentiatebetween black area descriptions and other area descriptions receivedfrom the LCS server.

An LCS server 700 and an LCS client 720 are schematically illustrated inFIG. 7 a, according to embodiments. Both the LCS server 700 and the LCSclient 720 may comprise a communication unit each 702, 722, forcommunicating with other network nodes or devices.

The LCS server 700 is configured to be used in a wireless communicationsystem for positioning of an LCS target. In one embodiment thepositioning is based on an adaptive enhanced cell identity method. TheLCS server 700 comprises a processing unit 701 configured to obtaininformation relating to a first predefined geographical area, wherein ithas been determined that a probability that the LCS target is locatedwithin the first predefined geographical area is below a threshold. Theprocessing unit is also configured to receive a request for apositioning of the LCS target, e.g. by using the communication unit 702,and to use the obtained information relating to the first predefinedgeographical area for the positioning of the LCS target. In oneembodiment, the processing unit 701 is further configured to store theobtained information relating to the first predefined geographical areain a database 703 and to retrieve the stored information based on thereceived request. The database 703 is in the embodiment illustrated inFIG. 7 a placed in the LCS server 700. However, it may also be placed insome other node such as the LCS target. In still another embodiment, theprocessing unit 701 is configured to obtain the information relating tothe first predefined geographical area by receiving the information froma network node. The information relating to the first predefinedgeographical area may comprise at least one of the following: a firstpredefined geographical area description; a second geographical areadescription associated with the first predefined geographical area; anda condition for when the first predefined geographical area isapplicable. The first predefined geographical area description may inone embodiment be a cluster of measurements with location informationfor LCS targets. Alternatively, the first predefined geographical areadescription may be a polygon determined based on the cluster ofmeasurements with location information for LCS targets. The conditionfor when the first predefined geographical area is applicable may bethat a time condition is fulfilled, or it may be that the LCS targetcorresponds to a specified LCS target. Furthermore, the first predefinedgeographical area may be at least one of the following: a physicallyrestricted area; a radio access restricted area; an area where an amountof measurements with location information is below a further threshold;and an area describing an overlap of two or more location areas.

According to embodiment A described above, the processing unit 701 maybe configured to use the information relating to the first predefinedgeographical area by adjusting a second geographical area descriptionassociated with the first predefined geographical area based on theinformation relating to the first predefined geographical area. Theprocessing unit 701 may also be configured to transmit the adjustedsecond geographical area description to an LCS client interacting withthe LCS server for the positioning of the LCS target.

Alternatively, the processing unit 701 may be configured to use theinformation relating to the first predefined geographical area byretrieving the second geographical area from the database, and storingthe adjusted geographical area description in the database. In thesealternative embodiments of how to use the information, the processingunit 701 may also be configured to adjust the second geographical areadescription by excluding a first predefined geographical areadescription comprised in the information relating to the firstpredefined geographical area from the second geographical areadescription. Alternatively, the processing unit 701 may be configured toadjust the second geographical area description by connecting a boundaryof a first predefined geographical area description comprised in theinformation relating to the first predefined geographical area with aboundary of the second geographical area description to form an extendedboundary comprising both of said boundaries, the extended boundarydescribing at least one area excluding the first predefined geographicalarea.

According to embodiment B described above, the processing unit 701 ofthe LCS server 700 may be configured to use the information relating tothe first predefined geographical area by transmitting the informationrelating to the first predefined geographical area to an LCS clientinteracting with the LCS server for the positioning of the LCS target.The transmitted information relating to the first predefinedgeographical area may comprise an indicator indicating whether ageographical area description in the transmitted information is a firstpredefined geographical area description.

An LCS client 720 is also illustrated in FIG. 7 a. The LCS client 720 isconfigured to be used in a wireless communication system for positioningof an LCS target, the positioning being managed by an LCS server 700interacting with the LCS client 720 for the positioning of the LCStarget. The LCS client 720 may in one embodiment be co-located with theLCS target. The LCS client 720 comprises a processing unit 721configured to receive information relating to a first predefinedgeographical area from the LCS server 700, e.g. by using thecommunication unit 722, wherein it has been determined that aprobability that the LCS target is located within the first predefinedgeographical area is below a threshold. The processing unit 721 of theLCS client 720 is also configured to use the received information forthe positioning of the LCS target.

The information relating to the first predefined geographical area maycomprise at least one of the following: a first predefined geographicalarea description; a second geographical area description associated withthe first predefined geographical area; and a condition for when thefirst predefined geographical area is applicable. The first predefinedgeographical area description may be a cluster of measurements withlocation information for LCS targets. The first predefined geographicalarea description may alternatively be a polygon determined based on thecluster of measurements with location information for LCS targets. Thecondition for when the first predefined geographical area is applicablemay be that a time condition is fulfilled, or that the LCS targetcorresponds to a specified LCS target. Furthermore, the first predefinedgeographical area may be at least one of the following: a physicallyrestricted area; a radio access restricted area; an area where an amountof measurements with location information is below a further threshold;and an area describing an overlap of two or more location areas. Thereceived information may also comprise an indicator indicating whether ageographical area description in the received information is a firstpredefined geographical area description. The processing unit 721 may beconfigured to use the received information by adjusting a position ofthe LCS target based on the received information.

FIG. 7 b schematically illustrates embodiments of the LCS server 700 andLCS client 720, which are alternative ways of disclosing the embodimentsillustrated in FIG. 7 a.

In FIG. 7 b, the LCS server 700 comprises the communication unit 702already described above, and a CPU 710 which may be a single unit or aplurality of units. Furthermore, the LCS server 700 comprises at leastone computer program product 711 in the form of a non-volatile memory,e.g. an EEPROM (Electrically Erasable Programmable Read-Only Memory), aflash memory or a disk drive. The computer program product 711 comprisesa computer program 712, which comprises code means which when run on theLCS server 700 causes the CPU 710 on the LCS server 700 to perform thesteps of the procedures described earlier in conjunction with FIG. 5 a.Hence in the embodiments described, the code means in the computerprogram 712 of the LCS server 700 comprises an obtaining module 712 afor obtaining information relating to a first predefined geographicalarea, a receiving module 712 b for receiving a request for a positioningof the LCS target, and a use module 712 c for using the obtainedinformation. The code means may thus be implemented as computer programcode structured in computer program modules. The modules 712 a-cessentially perform the steps 510, 520 and 530 of the flow in FIG. 5 ato emulate the LCS server 700 described in FIG. 7 a.

Furthermore, in FIG. 7 b, the LCS client 720 comprises the communicationunit 722 already described above, and a CPU 730 which may be a singleunit or a plurality of units. Furthermore, the LCS client 720 comprisesat least one computer program product 731 in the form of a non-volatilememory, e.g. an EEPROM (Electrically Erasable Programmable Read-OnlyMemory), a flash memory or a disk drive. The computer program product731 comprises a computer program 732, which comprises code means whichwhen run on the LCS client 720 causes the CPU 730 on the LCS client 720to perform the steps of the procedures described earlier in conjunctionwith FIG. 6 a. Hence in the embodiments described, the code means in thecomputer program 732 of the LCS client 720 comprises a receiving module732 a for receiving information relating to a first predefinedgeographical area from the LCS server 700, and a use module 732 b forusing the received information. The code means may thus be implementedas computer program code structured in computer program modules. Themodules 732 a-b essentially perform the steps 610, and 620 of the flowin FIG. 6 a to emulate the LCS client 720 described in FIG. 7 a.

Although the code means in the embodiment disclosed above in conjunctionwith FIG. 7 b are implemented as computer program modules which when runon the LCS server 700 and on the LCS client 720 causes the LCS serverand the LCS client to perform the steps described above in conjunctionwith FIGS. 5 a and 6 a respectively, one or more of the code means mayin alternative embodiments be implemented at least partly as hardwarecircuits.

Although the description above contains many specifics, they should notbe construed as limiting but as merely providing illustrations of somepresently preferred embodiments. The technology fully encompasses otherembodiments which may become apparent to those skilled in the art.Reference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.” Allstructural and functional equivalents to the elements of theabove-described embodiments that are known to those of ordinary skill inthe art are expressly incorporated herein by reference and are intendedto be encompassed hereby. Moreover, it is not necessary for a device ormethod to address each and every problem sought to be solved by thedescribed technology for it to be encompassed hereby.

ABBREVIATIONS 3GPP 3rd Generation Partnership Program AEDID AdapativeECID AGNSS Assisted Global Navigation Satellite System A-GPS AssistedGPS AoA Angle of Arrival BS Base Station

CDMA Code division multiple access

CID Cell Identity CN Core Network

CSG Closed subscriber group

E-CID Enahnced CID

eNodeB evolved Node B

E-SMLC Evolved Serving Mobile Location Center E-UTRAN: Evolution UMTSTerrestrial Radio Access Network FCC Federal Communications CommissionGAD Geographical Area Description GMLC Gateway Mobile Location CenterGPS Global Positioning Service HLR Home Location Register HSS HomeSubscriber Service LBS Location Based Services LCS-AP LCS-ApplicationProtocol LMU Location Measurement Unit LPP LTE Positioning Protocol

LPPa LPP annex

LTE Long-Term Evolution

MME Mobility management entity

MSC Mobile Switching Centre O&M Operation and Maintenance OTDOA ObservedTime Difference of Arrival PSAP Public Safety Answer Point RAN RadioAccess Network RF Radio Frequency RNC Radio Network Controller RRC RadioResource Control SLC SUPL Location Centre SLP SUPL Location Platform SONSelf Organizing Network SPC SUPL Positioning Center SRS SoundingReference Signal SUPL Secure User Plane Location TA Timing Advance TOATime Of Arrival UE User Equipment UMTS Universal MobileTelecommunications System UTDOA Uplink Time Difference Of Arrival UTRANUniversal Terrestrial RAN

WCDMA: Wide band code division multiple accessWGS World Geodetic System

1. A method in a location services, LCS, client of a wirelesscommunication system for positioning of an LCS target, the positioningbeing managed by an LCS server interacting with the LCS client for thepositioning of the LCS target, the method comprising: receivinginformation relating to a first predefined geographical area from theLCS server, wherein it has been determined that a probability that theLCS target is located within the first predefined geographical area isbelow a threshold, and using the received information for thepositioning of the LCS target.
 2. The method according to claim 1,wherein the information relating to the first predefined geographicalarea comprises at least one of the following: a first predefinedgeographical area description; a second geographical area descriptionassociated with the first predefined geographical area; and a conditionfor when the first predefined geographical area is applicable.
 3. Themethod according to claim 2, wherein the first predefined geographicalarea description is a cluster of measurements with location informationfor LCS targets.
 4. The method according to claim 2, wherein the firstpredefined geographical area description is a polygon determined basedon a cluster of measurements with location information for LCS targets.5. The method according to claim 2, wherein the condition for when thefirst predefined geographical area is applicable is that a timecondition is fulfilled, or that the LCS target corresponds to aspecified LCS target.
 6. The method according to claim 1, wherein thefirst predefined geographical area is at least one of the following: aphysically restricted area; a radio access restricted area; an areawhere an amount of measurements with location information is below afurther threshold; and an area describing an overlap of two or morelocation areas.
 7. The method according to claim 1, wherein the receivedinformation comprises an indicator indicating whether a geographicalarea description in the received information is the first predefinedgeographical area description, and wherein using the receivedinformation comprises adjusting a position of the LCS target based onthe received information.
 8. A location services, LCS, client configuredto be used in a wireless communication system for positioning of an LCStarget, the positioning being managed by an LCS server interacting withthe LCS client for the positioning of the LCS target, the LCS clientcomprising a processing unit configured to: receive information relatingto a first predefined geographical area from the LCS server, wherein ithas been determined that a probability that the LCS target is locatedwithin the first predefined geographical area is below a threshold, anduse the received information for the positioning of the LCS target. 9.The LCS client according to claim 8, wherein the information relating tothe first predefined geographical area comprises at least one of thefollowing: a first predefined geographical area description; a secondgeographical area description associated with the first predefinedgeographical area; and a condition for when the first predefinedgeographical area is applicable.
 10. The LCS client according to claim9, wherein the condition for when the first predefined geographical areais applicable is that a time condition is fulfilled, or that the LCStarget corresponds to a specified LCS target.
 11. The LCS clientaccording to claim 8, wherein the first predefined geographical area isat least one of the following: a physically restricted area; a radioaccess restricted area; an area where an amount of measurements withlocation information is below a further threshold; and an areadescribing an overlap of two or more location areas.
 12. The LCS clientaccording to claim 8, wherein the received information comprises anindicator indicating whether a geographical area description in thereceived information is the first predefined geographical areadescription, and wherein the processing unit is configured to use thereceived information by adjusting a position of the LCS target based onthe received information.
 13. A location services, LCS, system for awireless communications system for positioning of an LCS target,comprising: an LCS server and an LCS client for managing the positioningof the LCS target, the LCS server being configured to: obtaininformation relating to a first predefined geographical area, wherein ithas been determined that a probability that the LCS target is locatedwithin the first predefined geographical area is below a threshold,receive a request for a positioning of the LCS target, and send theinformation relating to the first predefined geographical area to theLCS client, and the LCS being configured to: receive the informationrelating to the first predefined geographical area from the LCS server,wherein it has been determined that a probability that the LCS target islocated within the first predefined geographical area is below athreshold, and use the received information for the positioning of theLCS target.